1. Field of the Invention
There are a number of screw fastening applications that require a pilot hole be drilled into the workpiece, a means provided for flush mounting or countersinking of a screw, and subsequently, a screw to be power driven into the workpiece. This task has commonly required (1) using two different tools, one for drilling and one for power driving a screw, or (2) removing the bit from the chuck of a drill and inserting a screwdriving attachment. The use of a single tool to perform the prescribed task with ease and quickness would be highly desirable.
It is the purpose of this invention to provide such a tool.
2. Description of the Prior Art
A tool is currently available which allows one to engage a specialty drill bit into a bit holder and to secure it in place by means of a set screw. Upon subsequent drilling of a pilot hole in a workpiece, a hollow cylyndrical screwdriver attachment is fitted over the drill bit and engaged with the bit holder in a fixed fashion, providing a set-up for powerdriving a screw. This device, while good for limited applications, has several disadvantages: (1) a specialty drill bit that will engage with the set screw on the bit holder is required; (2) there is no adjustment for easily setting a desired pilot hole depth; (3) there is no cutting action to provide the proper shaped hole for clean flush mounting or countersinking of a screw. This invention eliminates these problems.